Adjustable pitch propeller



P 1958 1 A. M. ROSSMAN 2,851,114

ADJUSTABLE PITCH PROPEILLER Original Filed June 20, 1949 s Sheets-Sheet 1 INVENTOR.

(Die n i7), Rossman.

p 9, 1958 A. M. ROSSMAN 2,851,114

ADJUSTABLE PITCH PROPELLER 1 Original Filed June 20, 1949 3 Sheets-Sheet 3 sew INVENTOR. 40 ll a WM/1mm we 18) I79 75 /A n5 United States Patent M ADJUSTABLE PITCH PROPELLER Allen M. Rossman, Chicago, Ill.

Original application June 20, 1949, Serial No. 100,235,

new Patent No. 2,681,632, dated June 22, 1954. Divided and this application November 16, 1953, Serial No. 392,250

2 Claims. (Cl. 170 16043 This is a division of application Serial No. 100,235, filed June 20, 1949, now Patent No. 2,681,632.

This invention relates to adjustable .pitch propellers and, more particularly, to such propellers as may be adjusted an amount suflicient to effect a complete reversal of the direction of drive by the propeller. In its more specific aspects the present invention is concerned with propellers for boats, wherein the speed isvaried by changing the propeller pitch. The invention is particularly applicable 'to propellers driven by outboard motors.

It is one of the objects of the present invention to provide an improved means for mounting an adjustable pitch propeller in a hub. In the preferred embodiment of the present invention the propeller blade is adjustable about an axis that extends radially ofthe axis about which the blade rotates when in operation. Each blade is adjusted angularly by means of an internal gear that is part of the propeller blade, and a pinion, one end of which is in mesh with the internal gear and the opposite end of which is in mesh with a rack that extends axiallyof the propeller hub. The pinion that connects the rack with the propeller blade is offset from a radial position in the hub. This offset facilitates the location of the propeller blades with their axes of adjustment extending radially, with a resulting improvement in theefficiency of the propeller blades. V

It is a further object of the present invention to provide improved means for holding the pitch adjusting pinion in the propeller hub. In accordance with. the principles of the present invention the pinion is located in a cylindrical bore in the hub, which bore is of a diameter onlysuflie ciently greater than the diameter of the pinion to allow a minimurn'of clearance between them. The cylindrical wall of the bore acts as a bearing for the pinion thus eliminating the need of a central bearing for the pinion.

The attainment of the above and further objects of the present invention will be apparent from the following 1 specification taken in conjunction with the accompanying drawings forming a part thereof.

In the drawings: Fig. l is an elevational view of an out oard motor. embodying the present invention; a Fig. 1a is a fragmentary sectional view taken. along the line la-la of Fig. 1;

Fig. 2 is an enlarged longitudinal sectional view of the gear housing which is the bottom of Fig. :1;

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a sectional view taken along the line 44 of Fig. 2;

Fig. 5'is a sectional view taken along the line 5-1- 5 of Fig. 2; i

Fig. 6 is'a sectional view taken along the line 66 of Fig. 5;

Fig. 7 is a view corresponding to Fig. 2 and illustratinganother embodiment of the present inventionp Figs. 8"and 10 are sections corresponding to Fig. 5

Figure 2 which shows a vertical cross section through and showing alternate ways of mounting the blades; 7

Fig. 9 is a section taken along the line 9-9 of Fig. 8,

and 1 Fig. 11 is a longitudinal sectional view showing this invention as applied to an inboard motor. 1 1

Reference may now be had more particularly to'the. drawings wherein like reference numerals designate like parts throughout. j

In Fig. 1 there is shown, at 1, an outboard motor embodying the present invention, said motor being shown as mounted on a boat in a conventional manner. .The stern of the boat is indicated fragmentarily at 2, and at 3 is indicated a bracket for mounting an outboard motor, that bracket being clamped to the stern in -the usualmanner. A motor supporting arm 5 is pivoted to the bracket 3 to swing about a horizontal pivot 6. A casing- 8 is supported on the arm 5, being pivoted to swing about an axis 9. The casing 8 constitutes at its upper end a support for aninternal combustionengine 10 and gasoline tank 11, and at its lowerend a support for. an underwater unit comprising a spacer 12 and-a gearcase 13. The casing 8 is mounted on the arm 5 in a conventional manner, and the engine 10 and'gas tank '11: are secured on the casing in the usual manner. The entire unit that is mounted on the arm 5 may be swung about the axis 9 by means of a handle 15 for steering the boat, as is conventional. The casing 8 also constitutes an underwater exhaust for the engine 10, as is usual in the art. The usual drive shaft from the engine extends through the casing 8 to the gear housing 13 for transmitting power to drive'the propeller, as will be more. fully described as this specification proceeds.-

Reference may now be had more particularly to propeller the gear housing 13. The gear housing 13 comprises acasting having a horizontal cylindrical portion 20 that is closed at one end by a curved wall 21 which is aniintegral part of the casting. There is thus formed a cylindricalspace 22 that is open at one end to receive the propeller hub and the gearing, bearings, etc., for the propeller. At this lower end the cylindrical portion 20 has a central fin 24 that acts as a rudder and also serves to protect the propeller from articles in the pathof the propeller, At its upper end the cylindrical portion 20-. has a lengthwise extending rib 25 for securing the gear housing to the rest of the motor unit. 1

On the interior of the cylindrical portion 20, at one end thereof, there are formed four inwardly projecting, lengthwise extending tracks 27 that constitute a support for a cam follower 28 which will be described more fullvas this specification proceeds. It is sufficient here to statethat the cam follower is movable longitudinally in the: cylindrical portion 20 when'actuated to do so by a camthat is splined on an axially rotatable pitch adjustingrod- 30. The cam follower 28 is non-rotatable and is provided for reciprocating a pitch adjusting shaft 35 that is low: gitudinally slidable in but rotates with a propeller hub 36.

The propeller hub includes a streamlined blade-receiving portion from which a hollow shaft 38 extends into the gear housing. The shaft 38 has a bevel gear 39 attheend thereof Within the housing and is journalled in a' thrust ball bearing 40 the outer race of which is pressed into a mounting ring 42 that is slip fitted into the housing and suitably gasketed at its outer periphery by a ring gas ket 43 to effect a water tight seal. A plate 44 assists-the thrust bearing 40 in preventing longitudinal movement of the shaft 38 and gear 39 in the assembled unit. The plate 44 bears against the ends 27 of the tracks 27 and may be held against rotation in any desired mannen: One suitable manner is that illustrated in Fig. 7 wherein a flat, headed screw is threaded in a countersunk bore in the Fatented Sept. 9, 1958 p 3 plate 44 and extends into a bore in the structure against which the left hand side (as seen in Fig. 7) of the plate 44 bears. A water sealing spring pressed packing 45 is provided for. elfeeting awater tight seal between the shaft 38 and the inner periphery of the ring 42. The ring 42 is maintained in place in the gear housing by a closure plate' 47- that is suitably bolted to the gear housing as by WQ bolts 48. To that efiect the closure plate 47 has a ring portion 49that engages .the end ofthe ring 42. The ple te47 also has a bushing 50 that constitutes a bearing for theshaft38. The shaft 38 is rotated by a bevel gear 5 that is in mesh with the gear 39. The bevel gear. 55 is keyed to a. drive shaft 56 thatis suitably journalled in ball b'earings 57 in the rib 25 of the gear housing 13. Atlits upper end the drive shaft 56 is driven by the internal combustion engine 10,

previously stated,- the pitch adjusting shaft 35 rotates with the shaft 38 but is longitudinally movable therein' A ball type thrust bearing 60 secures the Shaft 35 to'the non-rotatable cam follower 28 in such a manner that movement of'thecam follower to the right or to the leftresults in a correspondingmovement of the pitch adji istingshaft35',

cam follower 28 consistsof a solid cylindrical block ofSmetaI-thatisslabbedolf at the top, as indicated as 65 (Fig. 4), and that has a bearing-receiving bore 66 formedatj'one end thereof. The outer race of the ball bearihg 60-is secured within the bore' 66 and the inner. race is 'secnredto the pitch adjusting shaft 35, so that movement Of,'tl1e cam follower produces corresponding movement of the pitch adjusting shaft. In addition, the cam follower 28l1as a vertical slot 68 formed therein which extends through the full height of the follower, that slot being of sufficient width to permit the pitch adjusting rod 30to passtherethrough, and of alength in a horizontal direction suflicient topermit the follower the requisite freedom of. motion without the follower stopping against thepitehadjusting rod 30. The carn' follower 28 also has,

a horizontal slot 69 therethrough within which is located acarn 70-that is keyed to the pitch adjusting rod 30. The cam 70'may consist of a circular disk that is mounted on the pitch adjusting rod 30 eccentrically. The cam turns in the slot 69 and acts upon the walls 7171 of the cam follower to move the cam follower lengthwise on the tracks 27 27.

' The pitch adjusting shaft 35 has oneor more longitudinallycktending oil grooves 72in the periphery thereof to permit the exchange flow of oil between the hub 36 and the interiorof the gear housing as'the shaft 35 is moved. At the end of the pitch adjusting shaft 35 opposite the thrust bearing 60 the shaft has two gear racks. 75+75.

The portion of the hub 36 in which the propeller blades.

are mountedis streamlined. In the construction herein.

shown the hub is constructed to receive two propeller blades, indicated at 80-.80. For mounting each propeller blade the hub'36 is slabbed off to provide a fiat surface 8 l,-and ismachined to provide adeep annular groove 82. The outer Wall of. the groove 82 is screw threaded, as indicated at 83. The inner Walllis comparatiyely smooth, as indicated at 84. A cylindrical bore 85is formed in the hnh 36 extending from the fiat surface 81 to a depth appreciablygreater than the depth of theannular groove ,82. The bore 85 is eccentric of the groove82. Anelongated pinion 86 fits into the bore 85. The pinion is rotatable within the bore ,85, with the extremitiesof the teeth slid.- ing against the wall surface 85 of the .bore, whichsurface therefore acts as a journal for the pinion 86 within the boreQ The pinion 86. is in meshwiththe gear teeth:of the rack 75,-

Each propeller blade 80 has a shank 88 in the form of a ring that is externally threaded to engage the threads 83in the propeller hub. A ring gasket 89 is provided for sealing against the entrance of water into the hub at the joint between the propeller shaft and the hub. The shank 88-'has an internal ring gear 90 formed therein, the

teeth of which are in mesh with the pinion 86 and clear the smooth wall 84' of the deep groove 82. Thus, longi tudinal movement of the pitch adjusting shaft 35 turns the pinions 86 each of which pinions turns the corresponding propeller blade 80.

The gear case 13 is secured to the casing 8 in any desired manner, as by bolts 9293.

The pitch adjusting rod130 extends upwardly from the gear housing .13, through the spacer 12, and terminates at its upper end in two handle 9596. The handle 95 is keyed to the pitch adjusting rod 30 and is rotatable throughan angleof approximately 180 to effect the corresponding turning of the pitch adjusting rod 30. The handle 96 has a collar 97 as a part thereof, which collar is freely rotatable 0n the pitch adjusting rod 30. The collar 97 has a locking lug 98 integral therewith and extending radially therefrom. As the handle 96 is turned, the lug.98 comes into a position where it enters a slot in an arcuate flange 99 thatextends downwardly from the top of the mounting bracket 3 and is integral therewith. When the lug. 98 is outside of the slot theentire motorunitis free to turn about thepivot 6 as-a center. This turning is, necessary, to permit the underwater unit to swingclear ofia'ny obstructions that may be engaged by the rudder fin 24. When the handle 96 is turned to bring thelug 98 into, theslot in the flange 99 the lug prevents swinging. of theunit labout the pivot-6. This is necessary when themotor is driving the boat in reverse or when the boat is .coasting and moving at a speed greater than the speed'at which it wouldbe driven by the corresponding rotation.

The h'andles95 and 96 are arranged so that they can both be grippedin onehand simultaneously and both turned together. Turning of the handle 95 effects pitch adjustment. When the handle .95is in any position such thatjthe pitch of the propellertendstodrive the boat forward, the, corresponding: position of the handle 96 is such that the lug 98'is free .of its lockingzslot. When theha'ndleis in a position suchthat the propeller tendsto drive the ,boat backwards the corresponding position of the handle- 96 "is such thatthe lug-.98 is in locking engagement in its slot so thatthe motor unit 1 is locked against swinging about the .pivot 6 in adirection counter-clockwiseas seen in Figure 1.

While ,thebo'at is being manipulated,.cither during forward movement of the boat or backward movement ofthe'boat; orin changingfrom backingto forward movement, the two handles 95'and'96 are operated together. When it is desired to :change quickly from for- Ward'movement to rearward movement it is-desirable that the locking handle 96 be operated in advance of thehandle 95=to lock the motor unit against tilting be fore the pitch of the propeller has been-changed to reverse drive. This is due. to the fact thatat-times as the propeller pitch is being changed from forward to reverse movement, the reaction o f-the wateron the propeller due to the momentum of the boat may-tend to swingthe unit about thepivot 6 in adirectioncounter-clockwiseas seen in Figure I. This .actionmay take place even before the propeller has been adjusted tothe reverse driving position. To avoid that action-the handle 96 may be operated in advance of the handle. 95. to lock the unit against swin'gingabout the pivot 6.

e The thrust of the water'onlthe propeller blades may create a force tending to turn 'theblades within the hub. This turning action is transmitted through the'pinions 86to the rack 75 so that-there is anaxial thrust on the rotating shaft 35. This thrust is transmitted through the thrust bearing 60 to the cam follower, which in turn transmits it to the cam 70. As an aid in resisting this thrust the. bottom of the ;pitchcad iusting rod 30 is journalled in a groove at the bottom of the gear casing. The thrust of the cam follower 28- against the cam 70is a thrust between two. memberswthat. arestationary withrespect to one. another most of the time since the rotating .thrust is taken by the thrust bearing 60. The movement -between the cam 70 and the cam followery28 takes: place only when the .cam 70 is turned to adjust the pitch of the propeller.

In order to remove the gearing, etc., from within the housing 20 it is merely necessary .to slide the rod 30 upwardly out of the cam 70 and above the follower 68, then, upon unbolting the bolts' 48 theentiremechanism within the space 22 may be easily withdrawn through the open end of the housing.

The entire gear housing 13 may be filled with a lubricating grease or oil, which grease or oil extends also into the hub 36 and fills the spaces bet-ween the pinions 86 and the bore 85. The pitch adjusting shaft'35 has a pair of longitudinal grooves in the periphery thereofto permit the flow of oil from one end 'of'the shaft 'to the other end thereof as the shaft 35is moved further into or out of the propeller hub.

assure Reference may now be had more particularly to Figure 7 wherein there is shown a'modification of the embodiment of the invention previously. described. Insofar as the structure of Figure 7 is the same as Figure 6, identical reference numerals have been used. One of the difierences between the structure of Figure 7 and that of the embodiment previously described lies in the fact that instead of the ball bearing type of thrust bearing 60 at the end of the pitch adjusting shaft 35 there is here substituted an Oilite metal bearing 125 between the rotatable pitch adjusting shaft 35 and the reciprocating but non-rotatable carriage structure 128 that corresponds to the cam follower 28. The Oilite" bearing consists of very small metal particles pressed tightly together and sintered to form a porous mass, which mass is then impregnated with oil. The carrier 128, here as in the embodiment previously described, slides lengthwise in the gear housing 13'. This sliding movement is obtained by means of a rack 129 formed in the carriage, the rack having gear teeth in mesh with teeth 130 on the pitch adjusting rod 30'. The bevel gear 39 on the propeller shaft 38 is driven by the bevel gear 55 on the end of the engine driven shaft 56 as in the embodiment previously described, and thus drives the propeller shaft. In this instance the shaft 38' that corresponds to the shaft 38 of Figure 2 is journalled in a bearing 50 that is located in a ring 47 that is bolted to and constitutes a closure for the gear housing. A ring gasket 132 provides a water-tight seal between the closure plate 47' and the opening of the gear housing. A suitable water sealing gasket 133 seals against leakage of water into the gear housing around the periphery of the rotatable propeller shaft.

Reference may now be had to Figure 8 which is a view corresponding to Figure 5 and shows a modified hub structure. at 36, has integral therewith two opposite circular bosses 140 that are externally screw threaded, the threads terminating at an annular shoulder 141 that surrounds each boss, said shoulder having a peripheral groove therein for receivingra circular sealing gasket 143. Each boss 140 has a cylindrical bore 85 formed therein for receiving the pinion 86 that is in mesh with the teeth on the rack of the pitch adjusting shaft 35. The longitudinal axis of each bore 85 is parallel to the longitudinal axis of its boss and is located eccentrically thereof, as in the case of the corresponding bores of the structure of Figure 5. Each propeller blade, indicated at 80, terminates at a base 146 a portion of the outside of which is of the shape of a part of a sphere of the same radius as the radius of the spherical surface of the propeller hub 36'. The inside of the base has a bore therein that is internally threaded, as indicated at 147, to thread over the boss 140. At the end of the bore the base 146 has an internal gear 149 formed therein that is in mesh with the pinion 86. The base 146 has a counterbore that makes a sliding fit on the annular shoulder 141 of the hub 36' and makes a In this instance the hub structure, indicated sealing fit withthe gasket 143. It is believed that the operation of the pitch adjusting propeller, in theembodiment-illustrated in Figures 8 and 9, will be apparent from the description previously given in connection with the first described embodiment of the. invention.

The propeller of the present invention may include more than two propeller blades if desired. 'In Figure 10 there has been illustrated a manner of mounting three propeller blades on the hub of an outboard motor constructed in. the manner illustrated in Figures 1 and 2. In this instance the propeller hub is indicated at 36a and the rack end of the pitch adjusting shaft is indicated at. 35a. The pitch adjusting shaft 35a has three sets of racks, indicated at 75a, the racks being at 60 to one another. The propeller hub 36a in this instance has three hub-receiving slots or annular grooves 82 that are identical. with the grooves 82 illustrated in Figures 5 and 6, the three grooves 82 in Figure 10 being centered on axes apart, The three pinions-86 are mounted in bores 85, asin the embodiment illustrated in Figure 5, said bores being eccentric of the center of fiat surfaces 81 in the propeller hub structure.

Reference may now be had to Figure 11 that shows the present propeller mounting means as mounted on a hub of a boat driven by an inboard motor. The inboard motor and the connections therefrom for driving the propeller hub may be of any preferred construction. It is sufficient here to state that the underwater driving part of the unit includes a hub structure that is keyed to rotate with and be driven by an engine driven, axially rotatable drive shaft 171 that rotates the hub and with it the propeller blades that are mounted thereon. The hub structure includes a spherical portion 173 that has a cylindrical externally threaded shank 174 that is, in this instance, secured to the drive shaft by a threaded adaptor 175. A longitudinal cylindrical bore 178 is formedin the hub centrally thereof for receiving a pitch adjusting shaft 179 that rotates with the hub but is longitudinally slidable therein. The pitch adjusting shaft 179 is secured to a non-rotatable longitudinally movable shaft 180 by means of a thrust bearing structure 181. The thrust bearing structure is an Oilite bearing. The bearing consists of two parts screw threaded together and receiving between them a cylindrical disk head 183 that is centered on and secured to the shaft 179. The two Oilite parts are keyed together by a pin 185. The shaft 180 is secured to the hearing by a pin 186. As a result of this arrange ment the bearing is non-rotatable in the hub but is slidable therein, and the pitch adjusting shaft 179 rotates in the bearing.

A section of the hub structure, taken along the line a-a, would appear exactly as Figure 5, or as Figures 8 or 10, if those embodiments were used.

Adjustment of the pitch of the propeller blades is obtained by producing relative longitudinal movement of the pitch adjusting shaft 179 with respect to the hub 170. This may be done in either of two ways. In one type of inboard motor the hub structure 170 is mounted so that it cannot move longitudinally as it is rotated. In this type of structure pitch adjustment is made by moving the shaft 180 further into or out of the hub. In another type of inboard motor the shaft 180 is held against longitudinal movement and the rotatable drive shaft with its connected hub structure is mounted for controlled longitudinal movement so that as the hub is moved to the right or to the left, as seen in Figure 11, there is a corresponding rotation of the pinions 86 on the gear racks 75.

In compliance with the requirements of the patent statutes I have here shown and described a few preferred embodiments of my invention. It is, however, to be understood that the invention is not limited to the precise constructions here shown, the same being merely illusmounted for=angu1ar=pith adjustme'nt;an annular internal gear at the'inner 'endof the propller bladefor turning the blade in its pitch adjusting moveme t, said hubhaving a home pinion'in said bore, said pinion meshing with said internal gear'for imparting movement to same,

a raek longitudinally mounted in saidhfib andextending 10 along the axis of rotation thereof and meshing with said pinion, and means for imparting relative longitudinai motion between said rack and hub'for rotating said pinion.

-2. An adjustable pitch propeller comprising a rotatable hub,-an adjustable 'pith -propeiler blade on the hub and mounted forangular piteh adjustment, an annular internal gearat the inner end'of the 'propel'ler blade for turning the blade in its pitch'adjus'ting movement, said hub having a bore,--a' pinion in said bore, the Walls defining said bore slidably engaging 'the teeth of the "pinion thereby to F8 journfl'cmezpinicnxin saidsecond bore,=.saidrpinion=.1meshing '-with r-s'aid iinternal :ge'ar forzimpartingnnovcmem .10 samewa rack longitudinally' mounted in ilflid .hub *and meshing with said pinion, and means for impartingrreiativ'e longitudinal motion between said 1 rack andi hub for rotating-said: pinion.

References Cited in the file of'fliis' patent UNITED STATES PATENTS 612,315 Doran Oct. 11,1898 1,756,215 Schneider Apr. 29, 1930 1,875,598 'Heath Sept. 6, 1932 1,994,143 Martens Mar. 12,1935 .:2,314, 595 ."Patterson Mar. 23,.1943 2,374,833 Rippingille May 1, 1945 2,460,559 Wildhabei Feb. 1, 1949 FOREIGN PATENTS i 52 Great Britain of 1907 'GreabBi-itain Mar. 3, 1925 

